Subnets

DHCP client messages are sent to remote servers by BOOTP relay agents, which are often a feature of an IP router. Through the BOOTP relay agent, the DHCP server can tell which subnet a request came from. The BOOTP relay agent records which subnet the message came from in the DHCP message header. Then the DHCP server can use it to determine which network the client is on.

You cannot run a BOOTP server and a DHCP server on the same machine, because they both use the same port number. You can use the Solaris 2 DHCP server to serve BOOTP clients by turning on BOOTP compatibility mode.

With the DHCP protocol, a client that already has a leased or permanent IP address can get another lease on a temporary basis on another subnet. This is helpful for machines that sometimes must be moved from one location to another. This option is available if the server implementation supports such a feature.